A kind of electrochemical synthesis method of pyrido[1,2-a]benzimidazole compound

A benzimidazole and synthesis method technology, applied in the field of electrochemical organic synthesis, can solve the problems of low atomic efficiency, unfriendly environmental protection, high cost, etc., and achieve the effects of high reaction yield, simple and safe reaction system, and considerable yield

Active Publication Date: 2022-03-22
QILU UNIV OF TECH
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the deficiencies of the prior art, especially the problems of high cost, low atomic efficiency, and unfriendly environmental protection in the existing preparation methods, the present invention provides a more green and environmentally friendly synthetic pyrido[1,2-a]benzo Method for imidazoles

Method used

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  • A kind of electrochemical synthesis method of pyrido[1,2-a]benzimidazole compound
  • A kind of electrochemical synthesis method of pyrido[1,2-a]benzimidazole compound
  • A kind of electrochemical synthesis method of pyrido[1,2-a]benzimidazole compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0060] Example 1: Preparation of 8-chloro-2-fluorobenzo[4,5]imidazo[1,2-a]pyridine

[0061]

[0062] Add 0.2mmol of N-(4-chlorophenyl)-5-fluoropyridin-2-amine, 0.4mmol of potassium hexafluorophosphate, 0.4mmoL of sodium acetate trihydrate, and 5mL of water into a 10mL three-necked flask in sequence. The anode, the platinum electrode as the cathode, reacted at a constant current of 10mA for 16h under nitrogen conditions at 100°C, followed by TLC monitoring; after the reaction was completed, extracted with the extractant ethyl acetate, and the organic phase was removed by a rotary evaporator. The residue was purified by flash silica gel column chromatography (ethyl acetate:petroleum ether=1:3) to obtain the product with a yield of 89%;

[0063] 1 H NMR (400MHz, DMSO-d 6 )δ9.31(s,1H),8.47(s,1H),7.83(d,J=8.8Hz,1H),7.75(dd,J=10.0,5.2Hz,1H),7.68(td,J=9.0 ,2.0Hz,1H),7.51(dd,J=8.7,1.2Hz,1H);

[0064] 13 C NMR (101MHz, DMSO-d 6 )δ151.7(d,J C-F =234.2Hz), 146.83, 143.68(d, J ...

Embodiment 2

[0066] Example 2: Preparation of 2-fluoro-8-methylbenzo[4,5]imidazo[1,2-a]pyridine

[0067]

[0068] Add 0.2mmol of 5-fluoro-N-(p-tolyl)pyridin-2-amine, 0.4mmol of potassium hexafluorophosphate, 0.4mmol of sodium acetate trihydrate, and 5mL of water into a 10mL three-necked flask in sequence, and use a carbon rod as the anode. The platinum plate electrode is used as the cathode, under nitrogen condition, 100°C, react with a constant current of 10mA for 16h, TLC tracking and monitoring; after the reaction is completed, extract with the extractant ethyl acetate, the organic phase is removed with a rotary evaporator, and the residue Purified by flash silica gel column chromatography (ethyl acetate:petroleum ether=1:3) to obtain the product with a yield of 96%;

[0069] 1 H NMR (400MHz, DMSO-d 6 )δ9.07(s,1H),7.89(s,1H),7.64-7.49(m,2H),7.44(t,J=9.0Hz,1H),7.17(d,J=8.4Hz,1H), 2.37(s,3H);

[0070] 13 C NMR (101MHz, DMSO-d 6 )δ151.52(d,J C-F =232.4Hz), 145.74, 143.27(d,J C-F...

Embodiment 3

[0072] Example 3: Preparation of 8-(tert-butyl)-2-fluorobenzo[4,5]imidazo[1,2-a]pyridine

[0073]

[0074] In a 10mL three-necked flask, add N-(4-(tert-butyl)phenyl)-5-fluoropyridin-2-amine 0.2mmol, potassium hexafluorophosphate 0.4mmol, sodium acetate trihydrate 0.4mmol, 0.02mmol mercapto Methyl acetate, water 5mL, carbon rod as anode, platinum sheet electrode as cathode, under nitrogen condition, 100°C, react with constant current 10mA for 16h, track and monitor by TLC; after the reaction is completed, extract with ethyl acetate , the organic phase was removed by a rotary evaporator, and the residue was purified by flash silica gel column chromatography (ethyl acetate:petroleum ether=1:3) to obtain the product with a yield of 71%;

[0075] 1 H NMR (400MHz, DMSO-d 6 )δ9.37(s,1H),8.29(s,1H),7.74(d,J=8.7Hz,1H),7.69(dd,J=10.0,5.2Hz,1H),7.63-7.59(m,2H ),1.40(s,9H);

[0076] 13 C NMR (101MHz, DMSO-d 6 )δ151.57(d,J C-F =233.2Hz), 146.05, 144.91, 143.02, 129.89 (d, J C-F ...

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Abstract

The invention relates to an electrochemical synthesis method of pyrido[1,2-a]benzimidazole compounds, belonging to the technical field of electrochemical organic synthesis. The solvent, the electrolyte, the Lewis base, the 2-phenylaminopyridine compound, and the cathode and anode electrodes are sequentially added into the diaphragmless electrolytic cell, stirred, and reacted under constant current conditions. After the reaction is completed, the reaction solution is extracted, separated and purified to obtain the product pyrido[1,2-a]benzimidazole compound. The electrode used in the method described in this reaction is a general inert electrode, no need for electrode modification, and no additional addition of various metal catalysts, thereby avoiding the use of toxic, expensive and complex catalysts, high reaction yield, simple reaction system, simple and safe , suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of electrochemical organic synthesis, and relates to a synthesis method of pyrido[1,2-a]benzimidazole compounds, in particular to an electrochemical method for pyrido[1,2-a]benzimidazole compounds Preparation. Background technique [0002] Pyrido[1,2-a]benzimidazole is the core structure of many antibacterial drugs, anticancer drugs, and antiviral drugs. Pyrido[1,2-a]benzimidazole compounds have unique conjugated structure and electronic distribution, and often have strong fluorescence emission and high fluorescence quantum yield under electrical excitation, and have great biological activity and fluorescence. Broad spectrum, so this kind of compound has good optical properties. [0003] In 2010, Zhu et al [H.Wang, Y.Wang, C.Peng, J.Zhang, Q.Zhu, J.Am.Chem.Soc.2010,132,13217-13219.] reported a pyrido[ 1,2-a] The synthesis method of benzimidazole compounds, using copper (II) and iron (III) as a catalyst at...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): C07D471/04C25B3/09C25B3/05C25B3/11C25B3/07C25B3/20
CPCC25B3/00
Inventor陈建宾韩孝新
OwnerQILU UNIV OF TECH